George Galloway is given to hyperbole, but he did not exaggerate in boasting that the remarkable result he had achieved in Bradford West defied all recent precedent. Byelections are routinely an opportunity for insurgent outsiders, but few shoot from absolutely nowhere to victory. Fewer still claim an outright majority of the poll. Even Shirley Williams didn't quite manage that when she took Crosby with 49% of the ballot in the first flush of excitement which accompanied the 1981 birth of the SDP. You can ridicule Mr Galloway's talk of a "Bradford spring" whose sunlight will spread, but in one city, at least, he has broken the mould.

A cool reading of the numbers reveals that his Respect profited from losses made across the mainstream. Labour were indeed routed, but the Conservatives surrendered a slightly larger slice of the vote, haemorrhaging four votes for every five they had had in 2010. Meanwhile, the Liberal Democrats, who – in the half century since their predecessor party's win at Orpington – have been the automatic choice for that insurgent outsider role, instead broke down at the starting line, forgoing their deposit.

Having paid little heed to this contest until it was too late, Westminster's tribes may now simply brush it off. They will reason that Respect is little more than a platform for Mr Galloway's noisy one-man band, a peculiar mix of Marxism and mosque that might thrive in a byelection but would not convince anyone in a wider contest. They will reason, too, that this is an unusual constituency, one of a tiny handful where half the population stem from minorities, where ethnic factors loomed so large that Labour lost votes here in 1997, even as it swept them up nationwide.

There is truth in all this, but it is a complacent analysis – which disrespects Bradford's voters. A failing war in Afghanistan is a special concern for the Muslim community, but it is unpopular more widely too. With the mainstream meekly united behind that lost cause, it is no surprise if voters hunt around for ragbag alternatives. Beyond that, the result indicates the depth of disillusion in one working-class seat at a time of austerity. That is a problem for all parties, of course, but most particularly for Labour.

Whatever the detail of the figures, this was the opposition's seat to lose. It should have been looking to increase a majority, which instead disappeared. Just before the budget, polls were suggesting Labour had the edge – until adjustment was made for its supporters' reluctance to turn out, at which point the Conservatives took the lead. After a fortnight of blunders, the Tories' own standing has tanked. But the lesson of Bradford is that the Labour alternative is still dogged by the opposite of enthusiasm.